On Tuesday, February 23, 1993 at 6:12:17 PM UTC-8, Peter Mayne wrote:

In article <[email protected]>, [email protected] (Steve Loughran) writes:

I wonder if this is the first time hardware has been designed to
fit the OS?

Actually, it isn't.

VAX/VMS
OS/400 -> AS/400
SPARC for UNIX (and most RISC CPUs, for that matter)
8086 (for some kind of CP/M compatibility)
The CRISP processor specifically designed for C (see a recent Byte)

Peter is right in that RISC CPUs are normally optimised for the code which >is to be run on it, and given the amnout of CPU time the OS invariably >consumes that the OS must be used to determine which instructions
to provide[*] .Also things like memory protection models ought to match, >otherwise you get CPU designers coming up with bizarre segmented memory >architechtures when all us hackers want is a flat memory model ;-)

(but not Alpha 8->)

You mean no-one had a look at the instruction usage of any unix before >designing the architecture? Surely they didnt just use VMS.

The designers looked at application instruction usage. OS specific stuff
can be (and is) implemented in PALcode. Thus, OSF/1 isn't burdened by
OpenVMS features, Windows NT isn't burdened by OSF/1 features, etc, etc.

Oh yeah. MIPS processirs have had two endian modes for a long time. Something
to do with VaxStations I believe.

Only in the sense that DEC's MIPS chips ends are at the same end as VAXen ends.

Steve
[*] cynics may argue that in fact most modern RISC CPUS are optimised purely >for impressive benchmark figures.

A tempting argument... ;-)
PJDM
--
Peter Mayne | My statements, not Digital's.
Digital Equipment Corporation |
Canberra, ACT, Australia | "AXP!": Bill the Cat

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